If you are rearing mason bees, Osmia lignaria (the blue orchard
bee or the orchard mason bee) and O. cornifrons (the hornfaced bee)for
orchard pollination, you may want to provide plants nearby to prolong the
nesting period, and maximize your bee yields. The blue orchard bee is most
abundant in May though females may sometimes be present through mid-June,
depending on the weather. Unlike honeybees and bumblebees, you don't have
to supply flowers for the entire season to keep a colony alive. You just
want blooms for a couple of weeks beyond fruit tree bloom to keep the solitary
female foragers alive. Furthermore, you don't want plants that are more
attractive than your fruit trees while the trees are blooming, at least
not within the flight range of your bees.

Since you are probably interested in using these bees to pollinate fruit
trees, the best bet for maximizing the reproduction of Osmia is
to plant a diversity of fruit trees with staggered bloom. Put the bees
in the orchard when the first variety comes in to bloom, and they will
have trees to forage from for an extended period of time. At peak bloom
bees will move a maximum radius of about 11 tree rows. They will move further
at the end of bloom. If another set of trees comes into bloom a distance
away, they will abscond from their old nests to find a closer nesting site.
Bees can be moved overnight with some success from an orchard going out
of bloom to one coming in to bloom, but they must be moved at least 3 miles
to force them to reorient. It is best to have nests in a trailer if you
expect to have to move them around. This not only makes moving easier,
it also gives the bees a good landmark for orientation.

In addition to staggering bees on apricot, peaches, plums, cherries,
apple, and pear, consider ornamental varieties of these trees. The bees
don't care if the fruit is edible for people, they are interested in pollen
and nectar. Other plants in the Rose family, such as strawberries, raspberries,
blackberries, and of course, rose (single petal varieties) are probably
good choices.

Other trees, shrubs, and herbaceous plants are also acceptable for blue
orchard bees. The Catalog of Hymenoptera of America North of Mexico lists
many plants on which this species has been collected. The plants most likely
to attract blue orchard bees are listed in Table 1. O. cornifrons
will also forage from these species. The list is divided by plants where
O.
l. lignaria, the eastern and midwestern populations of this bee, were
collected, and plants where O. l. propinqua, the western populations
were collected. Many of the plants in the west will not grow very well
in the East, and vice versa. However, some plants could be listed in both
lists but are not, apparently because records of collections were only
made in one part of the country. Plants like rose, strawberry, clover,
crane's bill, radish and mustards will grow throughout the US, and are
likely to be attractive to O. lignaria. Contact a good nursery or
your Cooperative Extension Service Office for advice on what plants will
grow in your area, and whether they bloom before, during, or at the end
of fruit tree bloom. I've also put some comments and a rating system with
my impressions about which plants should or should not provide Osmia
with lots of pollen and nectar.

This list by no means exhausts the possibilities for Osmia forage.
In his book about the orchard mason bee, Brian Griffin raves about the
shrub Pieris Japonica (Andromeda japonica) for attracting Osmia
lignaria.
Suzanne Batra claims it also attracts O. cornifrons.
She also recommends two honeysuckle bushes, Lonicera fragrantissima
(Chinese winter honeysuckle) for before fruit bloom, and Lonicera tatarica
(Tatarian honeysuckle) for after fruit bloom. Look around the natural habitat,
and in your neighbor's yards for foraging Osmia to get more ideas.

Several species available commercially; some have escaped and become
a problem in California.

Prunus

Plum, prune, peach, nectarine, chokecherry

..

Ribes

Current, gooseberry

.

Rubus

blackberry, raspberry, thimbleberry

.

Salix

Willows

.

.

.

.

Perennials and Annuals

Amsinckia

Fiddleneck

wildflower

Brassica

Mustards

Annual; let them flower (bolt)

Clarkia

Godetia and others

Showy flowers; nice in a garden. Pollen may be too large for Osmia
to collect, but nectar will be attractive.

Hydrophyllum

Waterleaf

Wildflower

Nemophila exilis, menziesii

Baby blue eyes

.

Penstemon

Beard tongue

Not the red flowered species. Purples, blues may be ok.

Phacelia

Phacelia

Used by Phil Torchio to rear Osmia in the greenhouse, so it
must be a good choice.

Raphanus sativus

Radish

Let them bloom!

Salvia carduacea

Salvia, sage

Avoid reds, long-tubed flowers. Species grown as herbs may be especially
useful.

Senecio

Cineraria, Dusty Miller

Daisy-like flowers. Some are vines or shrubs.

Taraxacum vulgare

Mow them while fruit trees are in bloom, let them flower after

Trifolium repens

White clover

.

Vicia californicum

Vetch

.

(Source: Krombein et al., 1979, Catalog of Hymenoptera in America
North of Mexico.
Vol. 2 Smithsonian Institution Press p. 2032.
Common names were taken from the Sunset Western Garden Book,
1995,
and Peterson Guide to Eastern Wildflowers)

There are about 3,500 species of native bees in the USA. What can you
plant in your garden to attract native bees over the entire season?.

There is lots of information in gardening literature about plants that
attract butterflies and hummingbirds, but much less about plants that attract
bees, especially alternative bee species. Many flowers are known from scientific
literature to be pollinated by bumblebees, and there are scattered records
from taxonomic literature on the plants where solitary bees have been collected.
Here are some general suggestions. If you are interested in promoting pollen
bees in general, you want to have a variety of plants blooming in your
garden all season, to maintain a wide diversity of spring, summer, and
early fall bee species.

First, avoid horticultural plants that are described as "double". This
usually means that the plant has been selected to develop extra petals
instead of anthers. So there will be little or no pollen available for
bees. All bees need pollen as food for their offspring, and will not be
attracted to double flowers unless they happen to produce lots of nectar.
Marigolds, mums, many roses, etc. will attract few bees species unless
you plant the single varieties.

Bees tend to be attracted especially to flowers that are blue, purple,
and yellow. Many hummingbird pollinated flowers have evolved to be red
in color They also tend to have deep tubes. Butterflies may also be attracted
to such flowers. Hawkmoths also like deep-tubed white flowers, that produce
scent at night. Bees generally don't visit such flowers, although there
are exceptions. Flowers with short tubes or no tubes are more likely to
attract a variety of bees.

Members of the daisy family, Compositae, often attract lots of bees.
I've seen lots of bees on Cosmos, Zinnia, and Dahlia (single. Again, avoid
the double varieties. Sunflowers attract lots of native bees. The pollenless
varieties have only nectar rewards; you will attract more bees if you plant
sunflower varieties with pollen.

Members of the mint family are also attractive to many long-tongued.bees.
This includes many herbs such as sage (salvia), oregano, lavender, and
mint as well as native plants like Nepeta, and Stachys. Their nectar is
the main attractant.

Some leaf-cutting bees are attracted to members of the legume family,
particularly clovers, and sweet clovers. I've seen carpenter bees en masse
on Wisteria in the Boston area. Wisteria flowers require a large bee pollinator.

Long-tongued bumble bees are attracted to flowers with deep corollas
and hidden nectar spurs, as in larkspur, delphinium, monkshood, jewelweed,
bergamot, columbine, blue and yellow penstemons, false dragonhead, mimulus,
and snapdragon. They are great buzz pollinators of solanaceous flowers
such as nightshade, tomato, eggplant and potato, and bell shaped flowers
like blueberry and arctostaphylus.

Many of the plants mentioned above will attract mid and late-season
pollen bees and honeybees,but they bloom too late for Osmia,
which is active in the spring.

Do you have any favorite flowers, annuals, perennials, shrubs or trees
that attract alternative bees to your garden? Let me know and I'll include
them in a revised list in the future.

Two honeysuckle bushes provide food for hornfaced bees and orchard bees
before and after fruit trees bloom. They are perennial, non-invasive, and
easy to grow. Many other bee species, including honey bees, like them.